The pasting and blending images is one of the common operations implemented by most image manipulation systems. Such operations are a natural way to build complex images from individual pieces originating from different sources. For example, photographs can be easily combined with hand-drawn and computer generated images.
In contrast, pasting and blending tools are difficult to locate for surfaces. Most geometric modeling systems expect the user to manipulate control points of NURBS, individual mesh vertices and polygons, or to use conventional higher-level operations, such as volume deformations and boolean operations. In an image processing system, vertex and control point manipulation is equivalent to painting an image pixel-by-pixel. While it may be useful to have access to such low-level operations in certain cases, most image manipulations are performed using higher-level operations.
The concept of surface pasting was introduced in the work of Bartels, Mann and co-workers in the context of hierarchical splines. However, these authors did not specifically consider the more general surface types, and furthermore assumed that separate detail and base surfaces are given.
Moving existing features on a mesh was explored by Suzuki et al. An advantage of this approach is that no resampling of the repositioned feature is performed. However, continuous remeshing is required, which limits the complexity of the objects and features that can be handled. In addition, the issues of pasting features between surfaces and separation into base and detail are not considered by these authors.
The task of base/detail separation is similar to the construction of displaced subdivision surfaces. Parameterization algorithms are necessary for many geometric modeling and texturing applications, and a variety of algorithms have been proposed, including general parameterization algorithms in the context of reparameterization (changing connectivity to semi-regular) and texture mapping. Kuriyama and Koneko used local parameterizations to add offsets to a surface. The work of Pedersen on interactively placing textures on implicit surfaces is also relevant as it requires dynamic reparameterization of surface regions, similar to pasting.
As can be appreciated, the problems related to cutting and pasting images, and the blending of images from different sources, are still far from being adequately resolved.